Business taxes must be reformed to stop global giants like Google and Facebook negotiating sweetheart deals while small firms are left struggling, according to the leader of the Liberal Democrats.
Tim Farron will accuse the Government of "fawning" over big business as independent companies are being hit with rates they can barely afford.
He is bringing in former business secretary Vince Cable to lead an expert panel looking at ways to "radically reform" business taxation.
At the party's spring conference in York, Mr Farron will say: "Communities thrive when enterprise and small business can thrive. But far too often the cards are stacked against them.
"We currently have a broken tax system that allows Google and Facebook to negotiate for months, yet small businesses can't even get through on the phone.
"It's time we transformed the way we treat small business in this country. Instead of Government fawning over the conglomerates, and getting to small business later, how about putting small business at the centre of our business economy."
Mr Farron will also claim the UK is at an economic crossroads and accuse Chancellor George Osborne of planning "unnecessary" cuts in the Budget next week.
"We have already heard that more cuts are coming our way," he will say.
"George Osborne's approach to a budget is political theatre. It's about politics, headlines and calculated positioning.
"Not a long term economic plan, but a short term political scam.
"So, the UK now stands at a crossroads," he will add.
"Osborne is taking an unnecessary political choice to cut further.
"If the Chancellor really wanted to help the economy, he would invest in, and help our local communities."